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2010 Expedition to Antarctica

Week 5

Monday - Tuesday, January 25 - 26, 2010

Monday marked the close of our third week at sea. We used the day to complete our work in Barilari Bay, collecting a jumbo Kasten core with full recovery (6 m) and another Kasten core (1.3 m). Sampling the cores consumed the day and would not have been possible without the hard work of several people on board, including Dr. Ku Chul Yu and graduate student Sun Mi Jeong from the Korean Polar Institute (who both pulled double shifts on Monday), Yuribia Munoz, Dr. Scott Ishman, Dr. Amy Leventer, and Dr. Stefanie Brachfeld among others. As we finished sampling the first core, Dr. Domack summoned us from the back deck, where he had been cleaning the core barrel plates and sampling tools, and ordered us to go outside immediately. What a sight! As we motored out of Barilari Bay to head southward, we encountered some beautiful islands and a sailboat in our path. The sun was shining and playing on the shadows of the landscape, and Dr. Domack ensured that we all got our heads out of the mud to experience the view.

Just as we were celebrating a successful sediment core recovery, we received word from Site Beta that they had freed one of their ice drills that had gotten stuck at 380 m a few days ago. They hope to finish the full 430 meters of ice core in the coming days. Over the past week, a plan has been brewing between principle investigators on the ship, NSF, and the British Antarctic Survey to coordinate a stop at Rothera, the British Antarctic Survey (BAS) Base on Adelaide Island. At the start of the Larissa cruise, ice conditions on the eastern side of the Antarctic Peninsula not only prevented access to geology and biology sites but also made the distance from the ship to glaciology targets on the Peninsula too far for helicopter flights. We made the decision to transit to the western side of the Antarctic Peninsula, where the geology and biology teams could conduct surveys in the fjord systems and the glaciologists could access their sites from the backside. Unfortunately, weather conditions (i.e. cloud cover) on the western side of the Peninsula have stalled regular use of helicopter use on the ship, severely limiting glaciology work. Collaborating with Rothera personnel and by use of BAS's Twin Otter, a prop plane, would enable the glaciology team to complete all planned AMIGOS installations in the Larsen System. With all parties in agreement, we initiated the 12-hour transit out of Barilari Bay to Rothera Station. The plan was to drop off Dr. Martin Truffer, who remained on the ship while the other glaciologists installed AMIGOS at Site Beta, and the rest of the glaciology gear at Rothera. The ship would then leave the glaciologists at Rothera and head back to the eastern side of the Peninsula to try to access the Larsen System, where ice conditions have improved over the past three weeks. We will meet up with the glaciologists in two weeks and transit back to Punta Arenas at the end of February. The 12-hour transit brought us into breathtaking scenery with whales, seals, penguins, and ice bergs in our path. Early Tuesday morning, winding our way through Tickle Passage, we crossed the Antarctic Circle and made our way to the southern end of Adelaide Island to Rothera. As we navigated into port, the glaciology team that we had left at Site Beta greeted us with waving arms from Rothera point. Upon arrival, those involved with cargo unloading went straight to work, and the rest of us received a tour of the facility. We walked along the pebbly beaches of the island, encountering penguins and seals in our path, and capped the afternoon with proper English tea in the Bransfield House mess hall. All of us on board thank the people of Rothera for such a warm reception and BAS's willingness to help the Larissa Project.
 

Thursday - Saturday, January 27 - 29

Following our Rothera visit, the plan was to transit back to the Larsen System on the eastern side of the Peninsula, a journey of about 2.5 days. In route, we determined that an additional stop at Palmer Station, a U.S. Antarctic research base on Anvers Island, was needed to pick up laboratory supplies for work at the Larsen methane cold seep site. In preparation for the cruise, the principal investigators and NSF representatives meet countless times to strategically plan for the amount of supplies needed for such an expedition. With the unforeseen change in plans due to poor ice conditions, we used some of our supplies that was previously allocated for work in the Larsen System, on our work in the fjords on the western side of the Peninsula. Thus, we planned a quick stop at Palmer Station on Friday morning to pick up more nitrogen gas tanks, which are necessary to sustain an anoxic (without oxygen) glove box for Dr. Mike McCormick's analysis of bacteria and sediments that we will collect at the methane cold seep. In order to maximize time on the ship, we planned another sampling site in Barilari Bay before proceeding to Palmer Station on Friday morning. The stop allowed for the collection of another jumbo Kasten core that was 4.5 m in length and covers roughly 8,000 years of sedimentation. Dr. Ku Chul Yu and graduate student Sun Mi Jeong worked into the night, sampling the core for x-ray analysis. Their technique for preserving the sediment for x-ray analysis, which will be performed in their lab at the Korean Polar Research Institute, includes carefully filling thin, clear plastic trays with slabs of sediment in roughly 20-cm intervals. Their careful work on this core revealed fine laminations in the sediment. Laminations visually look like thin stripes of a different color or type of sediment in the core, and usually reveal a change in sedimentation. Further analysis of the sediment will tell us more about this early finding. Overall, the information that we will derive from this sediment core will complement the other two cores that we collected in the inner part of Barilari Bay. After our stop at Palmer Station, we secured our living and work spaces and have been making our way to the Larsen System. Within a few hours (Friday evening), we will be within range of Roberston Island, where we will be using helicopter support to install a GPS station and Dr. Greg Balco can sample for erratics. The term "erratics" refers to rocks that are not found locally, meaning that these rocks must have been transported from elsewhere by the ice. The location and elevation of where we find these erratics will tell us the position of past ice sheets. Greg Balco will search for erratics at different sites along the Peninsula and later perform cosmogenic-nuclide exposure dating on the rocks at his laboratory at the Berkeley Geochronology Center in California. The 2-day transit has give us all the opportunity to re-organize our laboratories for another month at sea and to catch up on some work. The Belgian ROV team has uploaded a series of still images from their previous ROV dives. Their imagery, including video, and sampling capabilities have given us a visual of the seafloor in several fjord systems on the western side of the Peninsula, and now we are all looking forward to using the ROV in the Larsen System. Check out a few of the still images on the Web site.
 

Saturday - Monday, January 30 - February 1

Monday, February 1st, marks the half-way point in the Larissa scientific research cruise. Four weeks ago today, we sailed through the Straits of Magellan and into the Drake Passage, making our way to the Larsen System. Ice floes, composed of thick ice blanketed with snow, blocked access to our target areas and forced a change in plans. Now, three weeks later, we have returned with a suite of geological and biological data from the western Antarctic Peninsula fjords to challenge the ice again. During our ventures in the west, we had been closely monitoring the ice via satellite as we hoped for westerly winds to break-up and help move the pack ice out of the Larsen System. We are currently back in the pack ice, just south of James Ross Island, which is a little farther south than our previous attempts. Although we are still making progress with the Palmer's ice-breaking capabilities, the landscape, now a canvas of white, offers no distinction between ice and sky. Our remote location makes many of us recall the stories of polar explorers that have come before us, from Sir Ernest Henry Shackleton and his crew on the Endurance in 1914, to the Swedish National Expedition from 1901 to 1904 on the Antarctica led by Captain Otto Gustaf Nordenskjold. Despite the loss of its ship in the pack ice, the Swedish crew established a base on Snow Hill Island, just to our east, and explored the areas surrounding the island.

Much has changed in the 100 years following these early expeditions. For one, our technologies have dramatically improved; we have traded wooden vessels for steel-enforced ice breakers, and we employ satellite imagery, GPS, radio, and email. Additionally, our purpose for sailing to the "bottom of the Earth" has shifted from adventure exploration to scientific exploration. As one of the most sensitive areas on Earth to regional climate change, the Antarctic Peninsula itself has experienced the loss of ice shelves and thinning glaciers overall the past 100 years. The Larissa project is especially interested in evaluating the response of the Antarctic Peninsula to the rapid loss of the Larsen B Ice Shelf in 2002. Although we are still making our way through the ice, we are in range of helicopter targets on Robertson Island, and will deploy them for GPS and glacial erratic work when cloud cover decreases. Meanwhile, we are continuing to conduct work in the labs and in briefings to plan for future operations, but a few of us will take a quick break tonight to wish Gent University graduate student Katrien Heirman a Happy Birthday with an ice cream cake in the galley.

On January 31, 2010, the Site Beta ice drilling team reached bedrock, after drilling the entire ice column (nearly 446 m of ice) at Bruce Plateau on the Antarctic Peninsula. An e-mail from the team states that they had a spectacular Sunday, even in the midst of a pretty windy snow storm. The core is in good shape and will receive further analysis back in the lab. We have hopes that the ice core, in tandem with marine sediment cores, will allow us to place the break-up of the Larsen B Ice Shelf and the retreat of tidewater glaciers in a paleoenvironmental context.


— Commentary and photos provided by Kimberly Roe '08